Display device having LTPS and oxide TFTs integrated on the same substrate

Patent metadata

Field	Value
Publication number	US-10312312-B2
Application number	US-201515520153-A
Country	US
Kind code	B2
Filing date	Dec 31, 2015
Priority date	Dec 31, 2014
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

Provided is a display device. A poly-Si layer is disposed on a substrate. A first metal layer is disposed on the poly-Si layer, and a metal oxide layer is disposed on the first metal layer. A second metal layer is disposed on the metal oxide layer. The first metal layer is overlapped with the second metal layer. The first metal layer and the second metal layer may be gate lines connected to different TFTs.

First claim

The invention claimed is:

1. A display device comprising:
a substrate;
a polycrystalline silicon (poly-Si) layer on the substrate;
a first metal layer on the poly-Si layer;
a metal oxide layer on the first metal layer;
a second metal layer disposed on the metal oxide layer and overlapped with the first metal layer;
a capacitor in which a first sub-capacitor, a second sub-capacitor, and third sub-capacitor are connected in parallel to each other, two terminals of the first sub-capacitor are the poly-Si layer and the first metal layer, two terminals of the second sub-capacitor are the first metal layer and the metal oxide layer, and two terminals of the third sub-capacitor are the metal oxide layer and the second metal layer; and
a first thin-film-transistor (TFT) and a second TFT are disposed in a pixel defined on the substrate,
wherein the poly-Si layer is an active layer of the first TFT, and the metal oxide layer is an active layer of the second TFT connected to the second metal layer, and
wherein the capacitor is provided in the pixel defined on the substrate.

2. The display device according to claim 1 , further comprising:
a plurality of switching thin-film-transistors (TFTs) and a driving TFT disposed in the pixel defined on the substrate,
wherein the first metal layer and the second metal layer are respectively connected to gate electrodes of different switching TFTs among the plurality of switching TFTs.

3. The display device according to claim 2 , wherein the first metal layer and the second metal layer are extended in the same direction.

4. The display device according to claim 2 , wherein the first metal layer and the second metal layer are gate lines.

5. The display device according to claim 2 , wherein one terminal of a switching TFT connected to the second metal layer is connected to a gate electrode of the driving TFT.

6. The display device according to claim 1 , further comprising:
a driving circuit disposed in a non-display area of the substrate and implemented with a plurality of TFTs,
wherein the first metal layer and the second metal layer are respectively connected to gate electrodes of different TFTs among the plurality of TFTs.

7. The display device according to claim 6 , wherein the driving circuit is a gate driver for providing one or more gate signals to the pixel defined on the substrate.

8. The display device according to claim 1 , wherein the poly-Si layer includes conductivized polycrystalline silicon,
the metal oxide layer includes conductivized metal oxide, and
the poly-Si layer, the first metal layer, the metal oxide layer and the second metal layer are overlapped with each other.

9. The display device according to claim 1 , further comprising:
the first TFT is a first switching TFT having one terminal connected to a first node;
a driving TFT having a gate electrode connected to the first node and one terminal connected to a second node;
the second TFT is a second switching TFT having one terminal connected to the second node; and
an organic light emitting diode connected to the second node, wherein the capacitor is connected between the first node and the second node.

10. The display device according to claim 9 , wherein the first metal layer includes the same material as a gate electrode of the second switching TFT, and
the second metal layer includes the same material as a gate electrode of the first switching TFT.

11. The display device according to claim 9 , wherein the second switching TFT is an oxide TFT, and the first switching TFT and the driving TFT are low-temperature polycrystalline silicon (LTPS) TFTs.

12. The display device according to claim 9 , wherein the first metal layer and the second metal layer are connected to the first node, and
the poly-Si layer and the metal oxide layer are connected to the second node.

13. The display device according to claim 1 , further comprising: a driving circuit disposed on a non-display area of the substrate and including the capacitor.

14. The display device according to claim 13 , wherein the driving circuit is a gate driver for providing one or more gate signals to the pixel defined on the substrate.

Assignees

• Lg Display Co Ltd

Inventors

• Kim Eui Tae
• Lee Bu Yeol

Classifications

• G02F1/1368

  in which the switching element is a three-electrode device {(G02F1/136277 takes precedence)} · CPC title

• G09G2340/0435

  Change or adaptation of the frame rate of the video stream · CPC title

• G02F1/136286

  Wiring, e.g. gate line, drain line · CPC title

• G09G2310/0262

  The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes · CPC title

• G09G2300/0417

  Special arrangements specific to the use of low carrier mobility technology · CPC title